In testing high density and high speed electrical devices such as LSI and VLSI circuits, a high performance probe card having a large number of contact structures must be used. In other application, contact structures may be used for IC packages as IC leads. The present invention is directed to a production process of such contact structures to be used in testing LSI and VLSI chips, semiconductor wafers, burn-in of semiconductor wafers and die, testing and burn-in of packaged semiconductor devices, printed circuit boards and the like, as well as used in forming leads of IC chips or IC packages.
The inventors of this application have proposed a new type of contact structure to be used in such applications in U.S. patent application No. 09/099,614 filed Jun. 19, 1998, entitled "Probe Contactor Formed by Photolithography Process", U.S. patent application No. 09/140,961 filed Aug. 27, 1998, entitled "High Performance Integrated Circuit Chip Package", and U.S. patent application No. 09/157,842 filed Sep. 21, 1998, entitled "Packaging and Interconnection of Contact Structure". This invention is directed to a method of producing contact structures shown in such patent applications.
In the above noted patent applications, the inventors have proposed a unique type of contact structures as shown in FIG. 1. The example of FIG. 1 shows the application in which contact structures 30 are mounted on a probe card to electrically contact the targets such as contact pads 320 on a printed circuit board 300. The contact structures 30 are formed through a photolithography process on a semiconductor substrate 20, which is fully described in the above patent applications.
Although the production methods introduced in the above noted patent applications appear to be successful, the methods require relatively many lithography steps to form the structure in a vertical direction on the substrate. The inventors have attained a more simplified and low cost production process which is also able to achieve contact structures of higher reliability because of the simplified production process.